The Structure of Plant Population of Forested Rangeland in Different Legal Definitions (Case Study: Sabzkouh Region, Chaharmahal & Bakhtiari Province, Iran) (original) (raw)
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Effects of plot size on assessment of tree species diversity in Caspian forests of Iran
Biodiversitas Journal of Biological Diversity
Tree species diversity is important to forest managers because any management that reduces tree species diversity may greatly reduce commercial benefits. Therefore, control over tree species diversity is an important aspect of hardwood forest management. An efficient and quick survey method is needed to facilitate the assessment of tree species diversity in forest stands. In this study, the effects of plot size on the assessment of tree species diversity were compared in the unevenaged hardwood stands in the Hyrcanian forests of Iran. There were selected 50 hectares of these forests representing the regional forests. Sampling procedures were carried out on concentric lozenge plots with different sizes, including 400, 800, 1000, 1200, 1600, 2000, 2500, and 5000 m 2 in the dimensions of 150×150m. For each plot, the type of the species and the number of trees were recorded. Shannon-Wiener (H '), Simpson (1-D), Mc-Arthur (N1), Hill (N2), Camargo (E'), Simpson (E1/D), Nee (EQ), Smith-Wilson (Evar), Menhinick (R2), Margalef (R1) indices were used to estimate of tree species biodiversity. The precision and cost criteria (E% 2 × T) were applied for a better evaluation of different plot sizes. The obtained inventory error values showed that Hill (diversity), Camargo (evenness) and Menhinick (richness) indices had the lowest inventory error in the different plot sizes. Also, the lowest value of inventory error in diversity, evenness and richness indices were related to plot sizes of 2500, 5000, and 5000 m 2 , respectively. Based on the obtained results of diversity and evenness indices, there was a significant difference between the different plot sizes and different indices. The results showed that the lowest value of E% 2 ×T for diversity, evenness and richness was related to Hill (800 m 2), Camargo (1000 m 2), and Menhinick (400 m 2). The finding results revealed that plot size had a significant effect on tree species' evenness.
Ecological Engineering, 2014
Beech forests are the richest forest community in Iran because they are both economically and environmentally valuable. The greatest forest volume occurs in Iran's beech forests. Forests dominated by oriental beech (Fagus orientalis Lipskey) cover about 565,000 ha and represent the total area of indigenous forests in Guilan Province. A system for classifying beech forests over such a large area is needed to aid its management. The aim of this study was to investigate the relationship between environmental factors with ecological species groups in unharvested beech forests in Guilan province in northern Iran using multivariate techniques of DCA and CCA. For this purpose, a random systematic 150 m × 200 m gird sampling plan was used to establish 60 1000 m 2 circular plots. In each plot, environmental factors (topographic and soil variables) and percent cover of each herbaceous species were recorded. The result of TWINSPAN analysis showed that six groups were distinct. Multivariate analysis was performed through CANOCO 4.5 to explore the relationship between the environmental factors and the plant community. The most important environmental factors associated with plant composition in beech communities were elevation, slope, slope aspect, N, P, K, pH, C, C/N ratio, organic matter, leaf litter, soil texture (clay, sand, silt) and EC. The use of natural vegetation as an indicator for site quality provides good results, due to the close relationship it has with abiotic site characteristics.
Arabian Journal of Geosciences, 2012
Vegetation indices have been introduced for analyzing and assessing the status of quantitative and qualitative characteristics of vegetation using satellite images. However, choosing the best indices to be used in forest biodiversity and vegetation is one of the important problems faced by the users. The purpose of this research is to evaluate six vegetation indices in the analysis of tree species diversity in the northern forests of Iran. The present research uses LISS III sensor data from IRS-P6 satellite. Geometric rectification of images was performed using ground control points, and Chavez model was used for atmospheric correction of the data. The six spectral vegetation indices included NDVI, IPVI, Ashburn Vegetation Index (AVI), TVI, TTVI, and RVI. Shannon-Wiener species diversity index was used to analyze diversity, and the value of the index was calculated in each sample plot. Then, the spectral values of each sample plot were extracted from different bands. The best subset regression was used to analyze the relationship between species diversity and the related bands. The results obtained from the regression showed that polynomial equations under scrutiny as independent variables can assess tree and shrub species diversity better than other bands and compounds used (R 2 00.47). The obtained results also indicated a higher capacity in the case of the AVI index for estimating tree species diversity in the under study area.
Biodiversitas, Journal of Biological Diversity, 2017
The aim of this study was to investigate vegetation composition in hardwood and coniferous plantations in 220 ha of Loblolly pine (Pinus taeda L.), Caucasian alder (Alnus subcordata C.A.Mey) and poplar (Populus deltoids) and its comparison with natural forests in Bibi Yanlu protected forest park in Astara, north of Guilan Province, Iran. Totally, 60 sampling plots of 1000 m 2 by systematic-random method using 150 × 150 m grid in plantation and 200 × 200 m in the natural forest were established. To study the biodiversity, Shannon-Wiener, Simpson's diversity indices, Hill evenness and richness indices were utilized. The results of this research showed that there is a significant difference for diversity and richness indices between natural forest and plantations. Diversity and richness indices in the natural forest were higher than Loblolly pine, poplar and alder plantations. The Hill evenness index between natural forest and plantations did not indicate significant differences. In terms of herbaceous and woody species similarity, alder plantation was closer to natural forest, and pine plantation had the least similarity with the natural forest.
Biodiversity and Conservation, 2010
Managers in conservation biology are continually faced with the dilemma of needing to demonstrate which areas should receive conservation priority based on the diversity of species contained. Darenasab (Hashtadpahloo) forest catchment with dominated oak species in Mediterranean forests of Zagross in Iran was chosen as a case study. In order to estimate plant species richness in different vegetation types at landscape level, field method that sample both trees and herbs strata simultaneously (modified multi-scale Whittaker plots) was used to make species–area curves. Twenty-one modified multi-scale Whittaker plots (250 m2 area) were located randomly in four vegetation types. Three species–area, species–log (area) and log (species)–log (area) curves models were constructed. The log (species)–log (area) model had the highest adjusted r2 among others. Based on Jaccard’s coefficient, the pure oak vegetation type was the most heterogeneous (22% overlap), and the cushion plants vegetation type is the most homogeneous (29% overlap). The slope of species–area curves had the least range (0.05) and the slope of species–log (area) curves had the largest range (4.38). When the slopes of species–log (area) curves divided by mean Jaccard’s coefficient, the species–log (area) curves estimated values closest to those observed. The index of vegetation types contribution to regional diversity for determining conservation priority in off-reserve area, based on ranking of the observed mean species per plots, slopes of the species–log (area) curves, mean of Jaccard’s coefficient, mean unique species per plot, and the number of threatened species in each vegetation types were calculated. This composite index may provide a scientific method to rank vegetation types with high conservation value.
This study was carried out on vegetation of Gisoum forest reserve with 171 hectares Area located in 14 km to Resvanshar city, Guilan province, to examine the structure and composition of the forest vegetation. The first topographic map of the area with the scale of 1:10000 was prepared and the study area was delimited. Transect- quadrate method of sampling was used to record the floristic and phytosociological data necessary for the analysis in about 44 quadrates of 400 m2. Some vegetation parameters viz. density and diameter at breast height (DBH) for trees (over story vegetation) as well as cover-abundance for under story vegetation were recorded, respectively. Life form spectrum of Raunkiaer, the dominant vegetation type of the area based on importance value and vegetation structure based on frequency classes, also their chorology caring a central importance in vegetation description were determined. The study of floristic list showed that 76 species belonged to 66 genera and 45 families existence in the area.The largest families were Asteraceae and Rosaceae with 5 species. Investigation on geographical distribution of plants species indicated that 44 % belonged to Europe – Siberian zone. Plant life forms by Raunkiaer method showed that phanerophytes with 35.5 % and hemicryptophytes with 27.6 % were the most frequent life forms. Dominant vegetation type based on importance value index was Buxus hyrcanus-Parrotia persica. Also the evaluating of vegetation structure based on frequency class revealed that abundance-distribution was irregular in under story and regular in upper story vegetation.
Plantations can help speed up secondary forest succession by improving soil conditions, attracting seed-dispersal agents and providing shadow necessary for under-story growth, in the present research, the naturally under-story regenerated native woody species diversity was studied in four tree plantations 22 years of age and it covers 42 ha, composed of Pinus brutia, Populus nigra L., Acer velutinum Boiss and Fraaxinus excelsior L. species, which is located in the South of town of Ghaemshahr in Berenjestanak lowland forest in the North of Iran, where there was remnant natural forest in each site, three plots 20 × 20 m are selected and one plot also implemented as the witness in natural forests around. Species-Area Curve was used for determining plots area. The number of woody plants (trees and shrubs) were enumerated and identified in each plot, and diameter and height of generated species were measured up to 1.3 m height. In order to analyse of biodiversity was applied heterogeneity Indicators of Shannon Wiener, Simpson, Brillouin, MacArthur's N1 and Hill's N2 as well as evenness by using Simpson, Smith and Wilsons, Camargos and modified Nee indices. Results of this study illustrate that about nines trees and shrubs species belonging to eights families were observed in study sites naturally that the highest and lowest number of woody species was nine and five in the F. excelsior L. and A. velutinum Boiss plantation, respectively. In all study sites, the highest and lowest value of heterogeneity indices is related to MacArthur's N1 and Simpson, respectively. The highest value of evenness indices in P. brutia, P. nigra L. and A. velutinum Boiss plantations belonged to the Simpson' s Index and in F. excelsior L. plantation and natural forest is related to Camargos index. The lowest value of evenness in all study areas was Modified Nee index. Results demonstrate that significant differences were observed in indices of heterogeneity (P = 0.0009) and evenness (P < 0.0001) amongst the planted areas and natural forest. Moreover, the highest value of heterogeneity and evenness were found in P. nigra L. (2.556) and A. velutinum Boiss (0.612) and the lowest values of these indices were in the nearby natural forest (1.818) and F. excelsior L. (0.257), respectively. There were no significant difference in species heterogeneity between F. excelsior L. and P. brutia as well as between F. excelsior L. plantations and natural forest at P = 0.05. Overall, species heterogeneity and evenness in the plantations was more than the surrounding natural forest. These results indicated that hardwood and coniferous tree plantations at this region not only reduce biodiversity (species heterogeneity and evenness), but also it has increased regeneration of woody species in all the plantations than the natural forest around. This could be effective tools in rehabilitating degraded lowland forest in the North of Iran.
Environmental Resources Research, 2016
The impacts caused by natural factors and human interventions during specific sampling periods have substantial influence on nature and the selected management method. The present research was carried out in Golestan Province forests, Iran over an 11-year period and the obtained data was analyzed based on systematic random sampling method with fixed sample plots (0.1 ha). The data including species, DBH, height, qualitative degree in the first six-meter of the stem, percentage of canopy, and regeneration status in sample plots were measured and recorded for sampled trees. The results showed that the sample plots in Golestan Province forests increased from 1018 at the beginning of the studied period (1996) to 1114, at the end (2007). The inventory performed in 2007 showed that considering the percentage of canopy, the areal percentage of these forests increased in 0-30% and >80% canopy classes compared to those in 1996; however, there was a considerable reduction in the percentage of canopy in the given forests in 30-50% and 50-80% classes. Comparing the productive and non-productive forests indicated that the area of protection and conservation forests increased in 2007 compared to that of the year 1996. The results also revealed that the number and volume per hectare of trees in Golestan Province forests were dramatically reduced to 53.6n.ha and 1104.9m 3 ha-1 respectively. This reduction was more remarkable for the main species of the studied forests including horn beam, chestnut-leaved oak, beech, and velvet maple. The highest reductions of number of tree species were observed in 20, 25, 30, 35, and 40cm diameter classes, while the variations of volume (vs. number) in diameter classes exhibited more fluctuations. Comparing the status of dead wood in the studied forests revealed that the highest number of dead wood (58.5%) and volume/ha (66%) occurred in horn beam compared to other species. The research also indicated that the highest abundance of regeneration pertained to seedling and sapling vegetation stages.
International Journal of Biology, 2011
In order to evaluation relationship between trees and shrubs biodiversity with some soil physical properties in hyrcanian forests, in range of 850-950 altitude from the sea level in 6 sites (in each site 30 plots) with least interfering of human in north aspect and with equal distance from each other were located. In this 20*50 meter frame, the characteristic of trees and shrubs species (Species name & diameter) recorded. The heterogeneity indices of simpson, shannon-wiener, simpson , s reciprocal, and number of equally common used for the quantitative data. In each plot, four soil samples (500g) taken in the depth ranges of 10-20-cm. After mixing its, one sample (200g) was selected for laboratory. Physical properties of used in research are soil texture (percent of sand, silt, and clay), percent of soil saturation and bulk density. Results showed sand percent have positive correlation in all sites except Carpineo-Paroteum type. In addition, results showed clay percent has negative correlation in all sites. Thus, according to special site condition in forest types, appropriate technique should be base on knowledge of qualitative and quantitative condition of communities.